Indoor unit displays E9; unit may stop and flash lights; sometimes associated with indoor coil or drain issues.

Safety: Turn off power at the breaker. Water and electricity are a dangerous combination; ensure the unit is dry before working on it.

Steps:

• 1. Check for water leaks: Remove the front cover and inspect the drain pan and PCB area for signs of water overflow or condensation dripping onto electronics.
• 2. Dry the unit: If moisture is present, gently dry the area with a cloth and allow the unit to air dry for several hours before reapplying power.
• 3. Inspect sensor harness: Follow the bundle of sensor wires from the coil to the PCB. Look for damaged insulation, pinched wires, or connectors contaminated with water or corrosion.
• 4. Reseat connectors: Disconnect and reconnect each sensor plug to ensure good contact.
• 5. Power reset: After ensuring everything is dry and reconnected, restore power and test the unit. If E9 clears and does not return, the issue may have been moisture-related.
• 6. Further diagnosis: If E9 persists, a technician should use the model-specific service manual to identify which sensor combination is triggering the protection and test each sensor and the PCB.